Core drill



1937- J. v. PENNINGTON 2,068,762

CORE DRILL Y Filed July 28, 19:4

ri F *1 2! 8 John K Pennington INVENTOR.

ATTORNEY.

The core barrel is indicated at 6.

Patented Jan. 26, 1937 UNITED STATES PATENT OFFICE 001m DRILL John V.Pennington, Houston, Tex., assignor to Reed Roller Bit Company, Houston,Tex., a

corporation of Texas This invention relates generally to deep welldrills and specifically to core drills.

It will be found particularly useful in that type of core drill-in whichcores or samples of the formation are taken at desired intervals as thedrilling proceeds without removing the drill stem from the well, thecorebarrel being dropped into the drill stem to descend by gravity toits core-receiving position adjacent the bit at the lower end of thedrill stem, and being removed upwardly thru the drill stem by means of acable, known as a wire line, which has attached to the lower end thereofa device known as an overshot, to engage the core barrel. In core drillsof the type just referred to, the

core barrel has heretofore been releasably connected to the drill stemby means of a latching device embodying various parts, the manufactureof which is costly and the operation of which is ineflicient; and as theinterengaging parts thereof are mounted in the stem and on the barrel tohold the latter at a pointnear the upper end thereof, it has beenimpossible to vary the length of the core barrel to obtain cores ofdif-' ferent lengths without removing the drill stem from the well andrepositioning such parts.

This invention has for its general object the provision of a core drillof the type just referred to, embodying a new and improved latchingdevice characterized by simplicity and consequent low cost ofmanufacture, and efiiciency in opera- 1 tion, and positioned in such amanner as to permit core barrels of various lengths to be 'usedtherewith for the purpose of taking cores of different lengths withoutremoving the drill stem detail fragmentary view ofthe lower portion ofthe core barrel with the snap ring thereon, and Fig. 3 a horizontalsection on' the line 3-3 of Fig. 1.

45 In the drawing the drill stem is indicated at I. It has on its lowerend a bit 2 of the conventional type which may include oppositelydisposed blades 3 and an annular central cutter 4 forming an opening 5for the reception of the core.

It has a head 1 adapted to be engaged by the overshot for a purposewhich will hereinafter appear, and a core catcher 8 that permits theentrance of the core into the barrel, and prevents the escape of 55 thecore therefrom. The core barrel 6 is made in two sections 9 and illwhich may be connected by'threads H. The lower section Ill fits within aliner l2 which has a flared upper end l3 and a tapered lower end M, theformer serving to guide the lower end of the bore barrel 6 into place,and 5 the latter fitting snugly in the bottom of the bit 2. The liner i2is pressed into the bit 2 and fits so tightly therein that it must beintentionally removed and is not disturbed by the removal of the corebarrel 6 in the manner hereinafter set 10 forth. On the lower end of thecore barrel is a tapered shoe I5 which rests upon the lower end of theliner M. Fitting in the annular groove [6 of the lower section Ill ofthe barrel 6 is a snap ring i'l having tapered upper and lower 15portions I8 and i9, the taper of the upper portion l8 being steeper thanthat of the lower portion l9; and for the reception of the ring I! theliner 12 has an internal annular groove 20, the upper skilledin the art.The numeral 22 indicates annular grooves in the liner H. for thereception of foreign matter entering between the liner l2 and sectionill of the core barrel 6. The numerals 23 and 24 indicate, respectively,an annular 30 "groove and ports in the liner H! to permit the escape offluid that might otherwise be trapped between the liner l2 and corebarrel, such fluid [being permitted to escape through the ports 25 ofthe bit head 2.

The numeral 26 indicates 35 uides to center the core'barrel 6 in thedrill stem I.

The drill may be used as follows:

If during the drilling of a well with the drill stem I and bit 2attached thereto; it is desired 40 to take a core, the core barrel 6 maybe dropped into the drill stem at the surface of the earth. It willdescend by gravity into the position shown by Fig. 1, the snap ring I!being radially compressed by the liner |2 as the tapered bottom portionI!) of ,the ring l1 slides thereinto, and said ring expanding when itreaches groove .20 in liner l2 to releasably hold the core barrel inplace. In view of the gradual taper indicated at I 9 the ring I! offersno objectionable resistance to compression as it enters the liner l2.

Rotation of the drill stem is then continued until the desired core hasentered the barrel 6, whereupon the conventional overshot may be loweredby means of a cable (neither of which is shown) until it engages thehead I, where-' upon the core barrel may be pulled upwardly through thedrill stem l, the initial upward force exerted being sufficient toovercome the resistance offered to upward movement of the core barrel bythe ring ll because of the relative steepness of the taper l8.

Now, if it is desired to take cores of different lengths, the uppersection 9 of the core barrel 6 may be disconnected from the lowersection I0 thereof, and a longer or a shorter section corresponding tosection 9 may then be connected to the lower section II], in view ofwhich it will be obvious that longer or shorter cores may be takenwithout altering in any way the elements of the latching device carriedby the core barrel, or the elements of the latching device carried bythe drill stem, because the lower section ID of the core barrel and theliner I2 may be used with sections thereabove of any length.

Various modifications and uses of the invention other than ashereinabove described will be apparent to those skilled in the art, allwithin the scope of the following claims.

I claim:

1. A core drill including a hollow drill stem; a drill bit secured tothe lower end of said drill stem and having a central opening, the lowerportion of the wall of said opening being tapered downwardly andinwardly; a liner in said opening and having a tapered lower end to fitthe lower portion of the wall of said opening, and having a flared upperend and an internal annular groove, the upper wall of said groove beinginclined upwardly and inwardly, and the lower wall of said groove beinginclined downwardly and inwardly; a core barrel having upper and lowersections separably connected together, said core barrel being insertabledownwardly in said drill stem until its lower section enters said liner;said lower section having a tapered lower end to fit the tapered lowerend of said liner, and having an external annular groove; a splitresilient latching ring in the groove in said barrel, and having atapered upper portion and a tapered lower portion, the taper of saidupper portion being steeper than the taper of said lower portion; saidring being automatically forced into said groove in said liner when saidcore barrel is moved downwardly, to releasably lock said core barrel inits core-receiving position, and being automatically forced out of saidgroove in said liner when an upward force is exerted on said corebarrel, to permit said core barrel to be removed through said drillstem.

2. A core drill includinm hollow drill stem; a drill bit secured to thelower end of said drill stem and having a central opening; a liner insaid opening; and having a flared upper end and an internal annulargroove; a core barrel having upper and lower sections separablyconnected together, said core barrel being insertable downwardly in saiddrill stem until its lower section enters said liner,'said lower sectionhaving an external annular groove; a split resilient latching ring inthe groove in said barrel, and having a tapered upper portion and atapered lower portion, the taper of said upper portion being steeperthan the taper of said lower portion; said ring being automaticallyforced into said groove in said liner when said core barrel is moveddownwardly, to releasably lock said core barrel in its corereceivingposition, and being automatically forced out of said groove in saidliner when an upward force is exerted on said core barrel, to

permit said core barrel to be removed through said drill stem.

3. A core drill including a hollow drill stem; a drill bit secured tothe lower end of said drill stem and having a central opening; a linerin said opening; said liner having an internal annular groove; a corebarrel insertable downwardly in said drill stem until it enters saidliner; said core barrel having an external annular groove; a splitresilient latching ring in the groove in said barrel, said ring beingautomatically forced into said groovein said liner when said core barrelis moved downwardly, to releasably lock said core barrel in itscore-receiving position, and being automatically forced out of saidgroove in said liner when an upward force is exerted on said corebarrel, to permit said core barrel to be removed through said drillstem.

4. A core drill including a hollow drill stem; a drill bit secured tothe lower end of said drill stem and having a central opening; a corebarrel insertable downwardly in said drill stem; a resilient latchingring; and an element to be engaged by said ring, said ring beingautomatically forced into engagement with said element when said corebarrel is moved downwardly, to releasably lock said core barrel in itscore-receiving position, and being automatically forced out ofengagement with said element when an upward force is exerted on saidcore barrel, to permit said core barrel to be removed through said drillstem.

5. A drill having a hollow drill stem; a bit connected to the lower endthereof; a core barrel insertable into and removable through said drillstem while the latter is in the well and having upper and lowerseparable core-receiving sections; and a latching device associated withsaid lower section to releasably hold said core barrel down in itscore-receiving position independently of said upper section, saidlatching device being freely rotatable with respect to said lowersection.

6. A drill including a drill stem; a core barrel; and a latching deviceto releasably hold said core barrel down in its core-receiving positionin said drill stem, said device including a resilient ring and meansautomatically engageable and releasable by said ring when said corebarrel is moved downwardly and upwardly, respectively, with respect tosaid drill stem.

7. A drill stem core barrel combination comprising a hollow drill stem,a core barrel arranged to move in said stem, and yieldable latchingmeans including a split ring arranged to releasably lock said barrel insaid stem.

8. A drill stem core barrel combination comprising a hollow drill stem,a core barrel arranged to move in said stem, and yieldable latchingmeans carried by said barrel to engage said stem including a split ring.

9. A drill stem core barrel combination comprising a hollow drill stem,a core barrel arranged to move in said stem, and yieldable latchingmeans including a split ring arranged to lock said barrel and stem incore-receiving position, said means positioned at the lower end of saidbarrel.

10. In a drill stem core barrel assembly the combination comprising ahollow drill stem having a drill bit on the lower end thereof and a corebarrel arranged to move freely in said stem,

of yieldable means freely rotatable with respect to said barrel forreleasably locking said barrel to said bit in core-receiving position.

11. In a drill stem core barrel assembly the 2,068,762 3 to move in.said stem, and yieldable latching prising a hollow drill stem, a corebarrel arranged means adjacent the lower end of said barrel toreleasably lock said barrel in said stem, said means having itsdownwardly facing projecting parts tapered at a relatively small angleto enable the core barrel in descending to move past obstructions in thewall of the drill stem without catching thereon.

JOHN V. PENNINGTON.

